Re: [PATCH] scsi: qla2xxx: Fix an integer overflow in sysfs code

2017-08-30 Thread Eric Dumazet
On Wed, Aug 30, 2017 at 6:12 AM, Greg KH  wrote:
> On Wed, Aug 30, 2017 at 03:21:07PM +0300, Dan Carpenter wrote:
>> The value of "size" comes from the user.  When we add "start + size"
>> it could lead to an integer overflow bug.
>>
>> It means we vmalloc() a lot more memory than we had intended.  I believe
>> that on 64 bit systems vmalloc() can succeed even if we ask it to
>> allocate huge 4GB buffers.  So we would get memory corruption and likely
>> a crash when we call ha->isp_ops->write_optrom() and ->read_optrom().
>>
>> Only root can trigger this bug.
>>
>> Fixes: b7cc176c9eb3 ("[SCSI] qla2xxx: Allow region-based flash-part 
>> accesses.")
>> Reported-by: shqking 
>> Signed-off-by: Dan Carpenter 
>
>
> Cc: stable 
>
> perhaps?
>
> thanks,
>
> greg k-h

Also a link to https://bugzilla.kernel.org/show_bug.cgi?id=194061
since shqking did a fair bit of analysis, not only report the bug.

Thanks.


Re: [PATCH] scsi: qla2xxx: Fix an integer overflow in sysfs code

2017-08-30 Thread Greg KH
On Wed, Aug 30, 2017 at 03:21:07PM +0300, Dan Carpenter wrote:
> The value of "size" comes from the user.  When we add "start + size"
> it could lead to an integer overflow bug.
> 
> It means we vmalloc() a lot more memory than we had intended.  I believe
> that on 64 bit systems vmalloc() can succeed even if we ask it to
> allocate huge 4GB buffers.  So we would get memory corruption and likely
> a crash when we call ha->isp_ops->write_optrom() and ->read_optrom().
> 
> Only root can trigger this bug.
> 
> Fixes: b7cc176c9eb3 ("[SCSI] qla2xxx: Allow region-based flash-part 
> accesses.")
> Reported-by: shqking 
> Signed-off-by: Dan Carpenter 


Cc: stable 

perhaps?

thanks,

greg k-h


Re: [PATCH] scsi: qla2xxx: Fix an integer overflow in sysfs code

2017-08-30 Thread Dan Carpenter
On Wed, Aug 30, 2017 at 08:28:52PM +0800, shqking wrote:
> Hi,
> 
> Glad to see it is fixed.
> 
> Can I apply for a CVE ID for this bug?
> 

We don't handle that on this list.  You'd need to ask on
oss-secur...@lists.openwall.com.

regards,
dan carpenter



[PATCH] scsi: qla2xxx: Fix an integer overflow in sysfs code

2017-08-30 Thread Dan Carpenter
The value of "size" comes from the user.  When we add "start + size"
it could lead to an integer overflow bug.

It means we vmalloc() a lot more memory than we had intended.  I believe
that on 64 bit systems vmalloc() can succeed even if we ask it to
allocate huge 4GB buffers.  So we would get memory corruption and likely
a crash when we call ha->isp_ops->write_optrom() and ->read_optrom().

Only root can trigger this bug.

Fixes: b7cc176c9eb3 ("[SCSI] qla2xxx: Allow region-based flash-part accesses.")
Reported-by: shqking 
Signed-off-by: Dan Carpenter 

diff --git a/drivers/scsi/qla2xxx/qla_attr.c b/drivers/scsi/qla2xxx/qla_attr.c
index 75c4b312645e..9ce28c4f9812 100644
--- a/drivers/scsi/qla2xxx/qla_attr.c
+++ b/drivers/scsi/qla2xxx/qla_attr.c
@@ -318,6 +318,8 @@ qla2x00_sysfs_write_optrom_ctl(struct file *filp, struct 
kobject *kobj,
return -EINVAL;
if (start > ha->optrom_size)
return -EINVAL;
+   if (size > ha->optrom_size - start)
+   size = ha->optrom_size - start;
 
mutex_lock(>optrom_mutex);
switch (val) {
@@ -343,8 +345,7 @@ qla2x00_sysfs_write_optrom_ctl(struct file *filp, struct 
kobject *kobj,
}
 
ha->optrom_region_start = start;
-   ha->optrom_region_size = start + size > ha->optrom_size ?
-   ha->optrom_size - start : size;
+   ha->optrom_region_size = start + size;
 
ha->optrom_state = QLA_SREADING;
ha->optrom_buffer = vmalloc(ha->optrom_region_size);
@@ -417,8 +418,7 @@ qla2x00_sysfs_write_optrom_ctl(struct file *filp, struct 
kobject *kobj,
}
 
ha->optrom_region_start = start;
-   ha->optrom_region_size = start + size > ha->optrom_size ?
-   ha->optrom_size - start : size;
+   ha->optrom_region_size = start + size;
 
ha->optrom_state = QLA_SWRITING;
ha->optrom_buffer = vmalloc(ha->optrom_region_size);